JPH0316490B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an operation control device for an internal combustion engine in which each cylinder is provided with a first intake passage and a second intake passage in which an intake control valve is provided.

Conventional technology The passage for each cylinder of the intake manifold is divided into two, and nothing is provided on the first intake passage side, but an intake control valve is provided on the second intake passage side, and this intake control valve is operated in a high rotation speed range or at a high rotation speed. The technique of increasing maximum output and increasing torque during low- and medium-speed operation by opening the valve only in the load range is known (Japanese Patent Application Laid-Open No.
57-105534, and Japanese Patent Application Laid-open No. 58-11919).

That is, in the conventional type described above, one parameter, for example, the rotation speed NE, is divided into a low and medium speed rotation range below a certain value No, and a high speed rotation area above a certain value No, and in the low and medium speed rotation range, the intake control By closing the valve and increasing the intake efficiency due to the intake inertia effect, increasing torque, and reducing blowback due to camshaft overlapping, internal
By reducing the amount of EGR and stabilizing combustion,
Generates swirl within the combustion chamber to improve combustion efficiency. On the other hand, in a high-speed rotation range, the intake control valve is opened to reduce intake air resistance and increase torque.

Problems to be Solved by the Invention However, in the conventional type described above, since the switching control parameter of the intake control valve is performed using one rotational speed parameter (or other load parameters may be used), it is difficult to obtain higher torque. The problem is that it is not possible.

Therefore, an object of the present invention is to obtain higher torque by controlling the opening and closing of the intake control valve while simultaneously considering the rotational speed and the load.

Means for solving the problem The means for solving the problem are shown in Figure 1.

In FIG. 1, in an internal combustion engine in which a first intake passage and a second intake passage in which an intake control valve is installed are provided for each cylinder, the rotational speed detection means detects the rotational speed NE of the engine, The rotation speed determination means determines that the rotation speed NE is in a low speed rotation range (for example, NE≦
4000rpm), medium speed rotation range (for example 4000rpm＜NE
<5000rpm) or high speed range (e.g. NE
≧5000rpm). On the other hand, the load detection means detects the engine load, such as the throttle valve opening (TA), and the load determination means determines whether the load is less than a predetermined load. As a result, the rotational speed
The closing control means closes the intake control valve when the rotation speed NE is in a low speed rotation range or when the rotation speed NE is in a medium speed rotation range and the load exceeds a predetermined load. On the other hand,
The closing control means opens the intake control valve when the rotational speed NE is in a high-speed rotational range or when the rotational speed NE is in a medium-speed rotational range and the load is less than a predetermined load.

Operation According to the means shown in FIG. 1, during medium speed rotation, the intake control valve is opened and closed according to the load.

Example The present invention will be explained in detail below with reference to Examples.

FIG. 2 schematically depicts a microcomputer-controlled multi-intake valve internal combustion engine as an embodiment of the present invention. In the figure, 10 represents an engine body, and 12 is an intake pipe communicating with an air cleaner (not shown). In the middle of the intake pipe 12, there is an air flow sensor 14 that detects the intake air flow rate.
A throttle valve 16 is provided downstream of the throttle valve 16 for controlling the intake air flow rate in conjunction with an accelerator pedal (not shown). The intake air that has passed through the throttle valve 16 is transferred to the surge tank 18.
The air is guided to the intake manifold 20 via. Each cylinder passage of this intake manifold 20 is divided into two, and an intake control valve 22 is provided in one of the passages. Assuming that the engine of this embodiment has four cylinders, the intake control valves 22 are provided for each cylinder, so a total of four intake control valves 22 are provided. Intake manifold 2
0 is connected to a combustion chamber 26 of each cylinder via an intake valve 24, and this combustion chamber 26 is connected to an exhaust manifold 30 via an exhaust valve 28.
In this embodiment, two intake valves 24 and two exhaust valves 28 are provided for each cylinder.

A fuel injection valve 32 is attached to each cylinder near the intake valve 24 of the intake manifold 20.
Each fuel injection valve 32 is an electronic control unit (ECU)
Input/output (I/
O) Opens and closes in response to electrical drive pulses sent through the interface 34a, and intermittently injects pressurized fuel sent from a fuel supply system (not shown).

Each cylinder is provided with a spark plug 36,
Ignition coil 40 via distributor 38
The ignition spark is generated by high-voltage current sent from the The ignition coil 40 is connected to an igniter 42, and the primary current of the ignition coil 40 is controlled intermittently in response to an ignition signal sent from the microcomputer in the ECU to the igniter 42 via the I/O interface 34a. As a result, ignition control is performed.

Each intake control valve 22 is driven to open and close by a diaphragm actuator 44. A negative pressure tank 48 is connected to the diaphragm chamber of the actuator 44 via a solenoid valve 46 . This negative pressure tank 48 is connected to the surge tank 18 via a check valve (not shown). I/O interface 3 from the microcomputer of ECU34
When a drive signal is sent through 4a and the solenoid valve 46 opens, negative pressure is transmitted to the actuator 44 and the intake control valve 22 closes. Conversely, the solenoid valve 46
When the valve is closed, the actuator 44 pushes up its diaphragm by the force of the built-in spring, thereby opening the control valve 22.

A throttle switch 50 is attached to the rotating shaft of the throttle valve 16. The throttle switch 50 is turned off when the opening degree of the throttle valve 16 is less than a predetermined opening degree, and turned on when it exceeds this opening degree. This predetermined opening degree is selected to be an opening degree close to the throttle valve 16 being fully open. Throttle switch 50
The output signal is sent to the microcomputer via the I/O interface 34a.

The air flow sensor 14 outputs a voltage according to the intake air flow rate Q, and this output voltage is output from the ECU 3.
Analog-to-digital (A/D) converter 34 in 4
b, converted into a binary signal, and then taken into a microcomputer.

Crank angle sensors 52 and 54 are attached to the distributor 38. These crank angle sensors 52 and 54 detect the crankshaft.
Each time the motor rotates by 30 degrees or 180 degrees, a pulse signal is output, sent to the ECU 34, and taken into the microcomputer via the I/O interface 34a. The rotational speed NE of the engine can be determined from the pulse signal at every 30° crank angle, and the top dead center position and cylinder are determined by the pulse signal at 180° crank angle.

In addition to the above-mentioned I/O interface 34a and A/D converter 34, the microcomputer includes a central processing unit (CPU) 34c, a random access memory (RAM) 34d, a read-only memory (ROM) 34e, and a control unit (not shown). It is equipped with circuits, clock generators, etc.

FIG. 3 is a sectional view of the intake passage and exhaust passage of each cylinder, viewed from above the cylinder. 24 is an intake valve, 2
6 is an exhaust valve, and 30 is an exhaust manifold. As described above, each cylinder passage of the intake manifold is divided into two, the first intake passage 56 and the second intake passage 58, and the above-mentioned intake control valve 22 is provided in the middle of the second intake passage 58. . Intake control valve 2
2 is open, intake air is sent to the combustion chamber through both the first and second intake passages 56 and 58, as shown by the solid line in the figure. When the intake control valve 22 is closed, the second intake passage 58 is closed, and the intake air is guided into the combustion chamber through only the first intake passage 56, as shown by the broken line in the figure.

Next, the operation of the aforementioned microcomputer will be explained. An interrupt is generated by a pulse signal every 30° of crank angle, which causes the engine rotational speed NE to
is required. This can be easily determined by taking the difference between the values of the free run counter for each interrupt at a crank angle of 30 degrees, and the reciprocal thereof corresponds to NE. The determined NE is stored at a predetermined location in the RAM 34d. Also, A/ of the intake air amount Q
The value after D conversion is also stored in a predetermined position in the RAM 34d each time.

From these NE and Q input data, the microcomputer calculates the basic injection pulse width TP for fuel injection control and the basic advance angle θ _BSE for ignition control using well-known methods, and also calculates the cooling water temperature, intake air temperature,
These are corrected according to the specific component concentration of the exhaust gas and other operational status parameters to obtain the final injection pulse signal and ignition signal. The obtained signals are sent to the fuel injection valve 32 and the igniter 42 at predetermined timings, thereby performing fuel injection control and ignition control. Since the contents of such fuel injection control and ignition control are well known, detailed explanation will be omitted.

FIG. 4 shows an example of a program for controlling the opening and closing of the intake control valve 22, and the intake control valve control will be explained below using the same figure.

During the main routine, the CPU 34c executes the process shown in the figure. First, in step 101, it is determined whether the rotational speed NE is 5000 rpm or more. If NE≧5000rpm, unconditionally step
Proceeding to step 102, a drive signal for opening the intake control valve 22 and closing the solenoid valve 46 is generated. In such a high rotational speed range, the intake control valve 22 is opened to open both the first and second intake passages 56 and 58 to reduce intake air resistance, thereby ensuring high output.

If it is determined that NE<5000rpm in step 101, NE is set to 4000rpm in the next step 103.
Determine whether the following is true. If NE≦4000 rpm, the process proceeds to step 104, where a drive signal is generated to open the solenoid valve 46 in order to close the intake control valve 22. That is, in a low rotational speed range such as NE≦4000 rpm, the intake control valve 22 is closed and the first intake passage 5 is closed.
Only 6 is opened. This improves the intake efficiency due to the intake inertia effect, increases torque, and reduces blowback due to camshaft overlap, which reduces the amount of internal EGR and stabilizes combustion. Additionally, swirl is generated within the combustion chamber, improving combustion efficiency.

If it is determined in step 103 that NE>4000rpm, that is, the rotational speed NE is 4000rpm<NE<
If the rotation speed is in the medium speed range of 5000 rpm, the program proceeds to step 105 and determines whether the throttle switch 50 is on or off. If the throttle switch 50 is off, that is, if the throttle opening is less than the predetermined opening, step 102 is performed.
Then, the intake control valve 22 is opened. Conversely, if the throttle switch 50 is on, that is, if the throttle opening exceeds the predetermined opening (almost fully open), the process proceeds to step 104, where the intake control valve 22 is closed.

A large shaft torque can be obtained by controlling the opening and closing of the intake control valve 22 depending on whether or not the throttle valve 16 is substantially fully open in the medium rotation speed range of 4000 rpm<NE<5000 rpm.
Fig. 5 shows the shaft torque characteristics with respect to the rotational speed NE, where A _WOT is when the throttle valve 16 is fully open and the intake control valve 22 is open, and B _WOT is when the throttle valve 16 is fully open and the intake control valve 22 is open. When A _P is closed, the throttle valve 16 is not fully open (constant at Q/NE = 1.0/rev), and the intake control valve 2 is
2 is open, B _P is the throttle valve 16
is not fully open (Q/NE=1.0/rev constant)
Each shows the characteristics when the intake control valve 22 is closed. As is clear from this figure, at high rotational speeds where the rotational speed NE is NE≧5000 rpm, regardless of whether the throttle valve 16 is fully open or not, it is better to open the intake control valve 22 (A _WOT ,
A _P ) can obtain larger shaft torque. Therefore, in this case, the intake control valve 22 is always open. In addition, in the low rotation speed range of NE≦4000 rpm, regardless of whether the throttle valve 16 is fully open or not, it is better for the intake control valve 22 to be closed (B _WOT , B _P )
Large shaft torque can be obtained. Therefore, in this case, the intake control valve 22 is always closed.
In the medium speed range of 4000rpm＜NE＜5000rpm,
When the throttle is fully open, the shaft torque is larger when the intake control valve 22 is closed (B _WOT than A _WOT ), and when the throttle is not fully open, the shaft torque is larger when the intake control valve 22 is open (A _P is larger). B) The shaft torque becomes larger than _P. Therefore, in this region, the opening and closing of the intake control valve 22 is controlled by the signal from the throttle switch 50 as described above.

FIG. 6 shows an example of a program in place of the control program shown in FIG. Steps 201 to 205 in the program in Figure 6 are steps 101 to 205 in Figure 4.
It performs exactly the same processing as 105. In the program shown in FIG. 6, if it is determined in step 205 that the throttle switch 50 is off,
In other words, if the throttle opening is less than the predetermined opening in the medium rotation speed range of 4000rpm<NE<5000rpm, the step
Proceeding to step 206, the ignition timing is advanced by a predetermined angle, for example, 3°C. That is, θ _BSE ← θ _BSE +
Perform correction processing at 3°C. Additionally, step 206
In this step, a process of reducing the fuel injection amount may be performed. Specifically, in step 206, processing is performed to reduce the correction coefficient ΔF for correcting the basic injection pulse width TP by a predetermined value _K1 . That is, ΔF←
Process ΔF−K ₁ . Next, the program proceeds to step 202, where the intake control valve 22 is opened.

When the throttle opening is below the specified opening in the medium rotation speed range of 4000rpm<NE<5000rpm, the intake control valve 2
By opening the valve 2, the torque can be increased as mentioned above, but this also allows the ignition timing to be advanced (closer to the MBT) since the limit for knocking can be increased. As a result, the torque can be further increased.
Figures 7a and 7b show the shaft torque characteristics with respect to the ignition timing. Figure 7a is when the throttle is fully open, and Figure 7b is when the throttle opening is not fully open but constant (Q/NE = 1.0/rev). It is a characteristic of
When the throttle is fully open, as shown in Figure 7a, the opening of the intake control valve 22 (A _WOT ) is more advanced than the knocking occurrence limit, and the basic advance angle θ _BSE is advanced accordingly. The basic lead angle calculation table is set in advance so that the When the throttle valve 16 is not fully open, as shown in FIG. 7b, when the intake control valve 22 is opened ( _AP is more advanced than _BP ), the knocking occurrence limit is located on the advance side. Therefore, in this case, as described above, it is possible to advance the ignition timing and obtain a large shaft torque. In this case, the basic lead angle calculation table is
It is tailored to B _P.

In addition, by advancing the ignition timing, the exhaust gas temperature can be lowered, making it possible to reduce the amount of fuel required for this purpose in the past, resulting in a reduction in fuel consumption. be able to.

In addition, instead of the above-mentioned throttle opening, other load parameters such as intake air amount per rotation,
Needless to say, intake air pressure or the like may be used.

Effects of the Invention According to the present invention, since the intake and exhaust valves are opened when the rotation speed is in the medium speed range and the load, for example, the throttle opening is less than a predetermined opening, the output torque in this range can be increased. Can be done. Furthermore, if the ignition timing is advanced in this region, the output torque can be further increased.
Further, it is possible to advance the ignition timing and reduce the fuel injection amount without increasing the exhaust gas temperature, and it is also possible to improve the fuel consumption rate.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the present invention, FIG. 2 is a diagram showing an outline of an embodiment of the present invention, FIG. 3 is a partial sectional view of an intake passage portion, and FIG. 4 is an example of a control program. FIG. 5 is a characteristic diagram of rotational speed versus shaft torque, FIG. 6 is a flowchart of an example of a control program, and FIGS. 7a and 7b are characteristic diagrams of ignition timing versus shaft torque. 10... Engine body, 12... Intake pipe, 14...
Air flow sensor, 16...Throttle valve, 18
...Surge tank, 20...Intake manifold,...
22...Intake control valve, 24...Intake valve, 32...
Combustion injection valve, 34... ECU, 36... Spark plug, 38... Distributor, 40... Ignition coil, 42... Igniter, 44... Actuator, 46... Solenoid valve, 48... Negative pressure tank ,
50... Throttle switch, 52, 54... Crank angle sensor, 56... First intake passage, 58...
...Second intake passage.

Claims (1)

[Scope of Claims] 1. In an internal combustion engine in which a first intake passage 56 and a second intake passage in which an intake control valve 22 is installed are provided for each cylinder, rotation for detecting the rotational speed (NE) of the engine. a speed detection means; a rotation speed determination means for determining whether the rotation speed is in a low speed rotation range, a medium speed rotation range, or a high speed rotation range; a load detection means for detecting the load (TA) of the engine; negative/lower discrimination means for determining whether the load of the engine is equal to or less than a predetermined load in a state close to full load; a closing control means for closing the intake control valve when the rotational speed exceeds the load; An operation control device for an internal combustion engine, comprising: opening control means for opening an intake control valve;